FAQ
+ How do I validate my new instrument?
You must verify that the test's performance in your laboratory is similar to the manufacturer's claims of accuracy, precision and reportable range. All related forms, printouts, control inserts, and reports will be maintained for the life of the system plus 2 years.
• Accuracy is determined by performing a multiplepoint linearity study. Linearity study must meet the minimum standards: Slope = 1.0 +/ 15% (0.85  1.15) R2 > 0.95
• Precision is determined by evaluating 15 level 1 or normal control results. Precision study must meet the minimum standards: Control mean +/ 2SD CV < 2.0% or as otherwise noted on the worksheet.
• Reportable Range is determined by demonstrating accuracy at a low, mid, and high point. Use data from Linearity Study.
• Verification of manufacturer's normal values is determined by comparing 5 nonpatient results against the manufacturer's normal values.
+ What is Lab Informatics /LIS
• Innovative Laboratory Record System (LRS) with similar qualities of a Laboratory Information System (LIS) will make operations in your lab or clinic run smoother.
• Introduction and implementation of a Laboratory Record System which Features a wide spectrum of online laboratory forms that can be customized to your testing needs.
o Patient registry logs
o Quality control logs
o Patient result logs for each test performed in your lab
o Laboratory instrumentation maintenance forms
o Temperature forms to monitor laboratory area, equipment and reagents/controls with specific temperature requirements
o Decontamination logs
o Maintenance logs for eyewash, microscopes, centrifuges and fire extinguisher
o Corrective action forms
• Provides our clients with the benefits of an online paperless LRS, with features designed to give them complete control over their laboratory in every step of the patient testing process.
• Ability to retrieve patient results and print patient result reports
• Provides new forms as testing facilities introduce new laboratory testing methods.
Forms That can be Incorporated in LRS
• Lab Test Forms
• Laboratory Result Forms
• Patient Test Results
• Maintenance
• Quality Control
• Master Logs
• Temperature Logs
• Customizable Forms
• Personnel Training
• Lab Policies & Procedure
+ Laboratory Mathematics
Calculation of "G" or RCF (Relative Centrifugal Force)
RCF is dependent on the speed of the rotor and the distance from the centre of the motor drive shaft to the base of the sample tube. Manufacturers will give you the maximum speed and RCF of the rotor and its radius. For any speed other than maximum, you need to calculate the RCF.
If you do not know the radius of the rotor, you will have to measure this. Sometimes this may entail a little bit of guesswork in the case of an angle rotor. The radius is measured from the centre of the rotor to the point that would be the bottom of the sample tube. Take into account, inserts and any tube cushions.
Insert the figures into the formula below or use a nomogram chart, if you have one, with a ruler on two values to determine the third. RCF and radius to obtain speed or radius and speed to obtain RCF. Nomogram for converting maximum relative centrifugal force (RCF, i.e., gforce) to RPM. www.aquaticpath.umd.edu/nomogram.html
Allows comparison of nonidentical data sets, i.e. two different procedures, etc., by expressing the standard deviation of each set as a percentage of the mean. CV is expressed as a %.
The formula is: CV=(SD/X) x 100, where SD= the standard deviation of a procedure and X= the mean.
Procedures with increasing CV values demonstrate decreased precision, since this reflects greater variability among the replicate samples. SlopeIntercept Formula y = mx + b
where m and b designate constants (the variable y is multiplied by the constant 1, which as usual is not explicitly written). The origin of the name "linear" comes from the fact that the set of solutions of such an equation forms a straight line in the plane. In this particular equation, the constant m determines the slope or gradient of that line; and the constant term b determines the point at which the line crosses the yaxis.
Mean
The mean is calculated by adding all of the values, and dividing by the number of values. The formula is:
For example, suppose you wanted to find the mean of the values 4, 6, 2, 8, and 5. The mean is:
X = mean n = the number of data points in set (total number of measurements) Σ = the sum of Xi = each measurement
Standard Deviation
The standard deviation (abbreviated s or SD) is calculated according to the following formula:
That is, calculate the deviation from the mean for each point, square those results, sum them, divide by the number of points minus one, and finally take the square root. For example, the deviations from the mean in the above example are 1, 1, 3, 3, and 0. The squared deviations are 1, 1, 9, 9, and 0. The standard deviation is therefore:
The standard deviation will be larger if the data are spread out and smaller if the data are closely clustered about the mean.
X = each data point n = the number of data points in set (total number of measurements) Σ = the sum of S = standard deviation √ = square root X = mean Xi = each measurement
Creatine Clearance (Urine creatinine X Urine volume) / (Serum creatinine X min. of duration) = (mL) / (min)
This value is then corrected for body surface area: Creatinine Clearance = ((mL) / (min)) x ((1.73 m2) / (Patient's surface area (m2)))
OR Urine Volume (mL/24 hours) / 1440 minutes per 24 hrs x urine creatinine/ serum creatinine x 1.73/ patient’s surface area
24 Hour Urine Creatinine Urine creatinine (mg/dL) x urine volume (mL/24 hrs) x 1dl/100 ml
24 Hour Protein Urine Protein (mg/dL) x urine volume (mL/24 hrs) x 1dl/100 ml
Corrected Ratio of blood to anticoagulant (the citrate concentration must be adjusted in patients who have hematocrit values above 55%.
C = Concentration C = 1.85 x0.001 (100HCT) x volume of blood For a 4.5 ml draw, C = 1.85 (0.001) (4.5) (100HCT) C = 0.008325 (100HCT)
Example: HCT= 65 in a 4.5 ml draw
C = 0.008325 (10065) C = 0.008325 (35) = 0.29 of sodium citrate needed 0.50 – 0.29 = 0.21 sodium citrate to be removed from a 4.5 ml tube
Chol/HDL Ratio
The total cholesterol to HDL cholesterol ratio (total chol/HDL) is a number that is helpful in estimating the risk of developing atherosclerosis. The number is obtained by dividing total cholesterol by HDL cholesterol. (High ratios indicate a higher risk of heart attacks, whereas low ratios indicate a lower risk).
Chol/HDL ratio = Chol/ HDL
Free Thyroxine Index Formula The FTI tells how much T4 is present compared to the thyroxinebinding globulin. The FTI can help tell if abnormal amounts of T4 are present because of abnormal amounts of thyroxinbinding globulin. FTI = T3U x T4
100 % Error % error = actual value  theoretical value X 100 theoretical value
